1. Technical Field
The present invention relates to a communication apparatus control program and a communication apparatus which notify another communication apparatus that a communication apparatus to be handled is connected to a network.
2. Description of the Related Art
A ubiquitous environment requires a scheme which cooperates with services and equipments that subsist in a particular place. At present, notice is taken of the UPnP (Universal Plug and Play) as standard technology for the cooperation.
Here, the operation of UPnP equipment will be described.
First, the existence notification (ALIVE) of the UPnP equipment will be explained. Here, the UPnP equipment which is to be handled shall be called “UPnP equipment to-be-handled”. A network to which the UPnP equipment to-be-handled is connected shall be called “network to-be-handled”.
During the connection of the UPnP equipment to-be-handled to the network to-be-handled, the UPnP equipment to-be-handled transmits the existence notification to the network to-be-handled by multicasting. The notification indicates the existence of itself to other UPnP equipment located within the network to-be-handled.
The existence notification bears an available term. Besides, the UPnP equipment to-be-handled transmits the existence notification again before the available term expires. The other UPnP equipment, having received the existence notification, regards the UPnP equipment to-be-handled as existing within the available term. The other UPnP equipment regards the UPnP equipment to-be-handled as having gone out of existence upon the expiration of the available term.
Next, the stop notification (BYEBYE) of the UPnP equipment will be explained. When the UPnP equipment to-be-handled is to be detached from the network to-be-handled, it transmits the stop notification by multicasting to the network to-be-handled. The other UPnP equipment having received the stop notification regards the UPnP equipment to-be-handled as having gone out of existence, even when the available term remains.
Incidentally, as a related-art technique relevant to the Embodiments, there has been a network apparatus wherein individual devices within a network manage the information items of the devices found out one another, as a list. The information items are shared by notifying disconnection from the network and the like changes, among the devices, so as to periodically confirm the existences of the devices (refer to, for example, JP-A-2004-318852).
However, the existence/stop notifications of the UPnP are not interlocked with the connection/detachment to and from the network. Therefore, when the UPnP equipment to-be-handled is detached without sending the stop notification, the other UPnP equipment regards the UPnP equipment to-be-handled as existing, until the available term expires. In a case, for example, where the UPnP equipment to-be-handled connected to the network by radio communications, and UPnP equipment to-be-handled goes out of the area of the radio communications, it is detached from the network without sending the stop notification. Besides, the ordinary available term is set at, for example, 30 minutes. In this case, the other UPnP equipment regards the UPnP equipment to-be-handled as existing, for at most 30 minutes.
With the related-art technique mentioned above, all the devices monitor one another at all times, so that the load of all the UPnP equipments is heavy. If the UPnP equipment to-be-handled is battery-driven, the operating time period of the UPnP equipment to-be-handled shortens when the loads of a CPU and the radio communications are increased.